summaryrefslogtreecommitdiffstats
path: root/kpdf/xpdf/xpdf/SecurityHandler.cpp
blob: 6c2abba097740efcb31d0b1e1e3cbda2065347cf (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
//========================================================================
//
// SecurityHandler.cpp
//
// Copyright 2004 Glyph & Cog, LLC
//
//========================================================================

#include <aconf.h>

#ifdef USE_GCC_PRAGMAS
#pragma implementation
#endif

#include "GString.h"
#include "PDFDoc.h"
#include "Decrypt.h"
#include "Error.h"
#include "GlobalParams.h"
#if HAVE_XPDFCORE
#  include "XPDFCore.h"
#elif HAVE_WINPDFCORE
#  include "WinPDFCore.h"
#endif
#ifdef ENABLE_PLUGINS
#  include "XpdfPluginAPI.h"
#endif
#include "SecurityHandler.h"

//------------------------------------------------------------------------
// SecurityHandler
//------------------------------------------------------------------------

SecurityHandler *SecurityHandler::make(PDFDoc *docA, Object *encryptDictA) {
  Object filterObj;
  SecurityHandler *secHdlr;
#ifdef ENABLE_PLUGINS
  XpdfSecurityHandler *xsh;
#endif

  encryptDictA->dictLookup("Filter", &filterObj);
  if (filterObj.isName("Standard")) {
    secHdlr = new StandardSecurityHandler(docA, encryptDictA);
  } else if (filterObj.isName()) {
#ifdef ENABLE_PLUGINS
    if ((xsh = globalParams->getSecurityHandler(filterObj.getName()))) {
      secHdlr = new ExternalSecurityHandler(docA, encryptDictA, xsh);
    } else {
#endif
      error(-1, "Couldn't find the '%s' security handler",
	    filterObj.getName());
      secHdlr = NULL;
#ifdef ENABLE_PLUGINS
    }
#endif
  } else {
    error(-1, "Missing or invalid 'Filter' entry in encryption dictionary");
    secHdlr = NULL;
  }
  filterObj.free();
  return secHdlr;
}

SecurityHandler::SecurityHandler(PDFDoc *docA) {
  doc = docA;
}

SecurityHandler::~SecurityHandler() {
}

GBool SecurityHandler::checkEncryption(GString *ownerPassword,
				       GString *userPassword) {
  void *authData;
  GBool ok;
  int i;

  if (ownerPassword || userPassword) {
    authData = makeAuthData(ownerPassword, userPassword);
  } else {
    authData = NULL;
  }
  ok = authorize(authData);
  if (authData) {
    freeAuthData(authData);
  }
  for (i = 0; !ok && i < 3; ++i) {
    if (!(authData = getAuthData())) {
      break;
    }
    ok = authorize(authData);
    if (authData) {
      freeAuthData(authData);
    }
  }
  if (!ok) {
    error(-1, "Incorrect password");
  }
  return ok;
}

//------------------------------------------------------------------------
// StandardSecurityHandler
//------------------------------------------------------------------------

class StandardAuthData {
public:

  StandardAuthData(GString *ownerPasswordA, GString *userPasswordA) {
    ownerPassword = ownerPasswordA;
    userPassword = userPasswordA;
  }

  ~StandardAuthData() {
    if (ownerPassword) {
      delete ownerPassword;
    }
    if (userPassword) {
      delete userPassword;
    }
  }

  GString *ownerPassword;
  GString *userPassword;
};

StandardSecurityHandler::StandardSecurityHandler(PDFDoc *docA,
						 Object *encryptDictA):
  SecurityHandler(docA)
{
  Object versionObj, revisionObj, lengthObj;
  Object ownerKeyObj, userKeyObj, permObj, fileIDObj;
  Object fileIDObj1;
  Object cryptFiltersObj, streamFilterObj, stringFilterObj;
  Object cryptFilterObj, cfmObj, cfLengthObj;
  Object encryptMetadataObj;

  ok = gFalse;
  fileID = NULL;
  ownerKey = NULL;
  userKey = NULL;

  encryptDictA->dictLookup("V", &versionObj);
  encryptDictA->dictLookup("R", &revisionObj);
  encryptDictA->dictLookup("Length", &lengthObj);
  encryptDictA->dictLookup("O", &ownerKeyObj);
  encryptDictA->dictLookup("U", &userKeyObj);
  encryptDictA->dictLookup("P", &permObj);
  doc->getXRef()->getTrailerDict()->dictLookup("ID", &fileIDObj);
  if (versionObj.isInt() &&
      revisionObj.isInt() &&
      ownerKeyObj.isString() && ownerKeyObj.getString()->getLength() == 32 &&
      userKeyObj.isString() && userKeyObj.getString()->getLength() == 32 &&
      permObj.isInt()) {
    encVersion = versionObj.getInt();
    encRevision = revisionObj.getInt();
    encAlgorithm = cryptRC4;
    // revision 2 forces a 40-bit key - some buggy PDF generators
    // set the Length value incorrectly
    if (encRevision == 2 || !lengthObj.isInt()) {
      fileKeyLength = 5;
    } else {
      fileKeyLength = lengthObj.getInt() / 8;
    }
    encryptMetadata = gTrue;
    //~ this currently only handles a subset of crypt filter functionality
    if (encVersion == 4 && encRevision == 4) {
      encryptDictA->dictLookup("CF", &cryptFiltersObj);
      encryptDictA->dictLookup("StmF", &streamFilterObj);
      encryptDictA->dictLookup("StrF", &stringFilterObj);
      if (cryptFiltersObj.isDict() &&
	  streamFilterObj.isName() &&
	  stringFilterObj.isName() &&
	  !strcmp(streamFilterObj.getName(), stringFilterObj.getName())) {
	if (cryptFiltersObj.dictLookup(streamFilterObj.getName(),
				       &cryptFilterObj)->isDict()) {
	  cryptFilterObj.dictLookup("CFM", &cfmObj);
	  if (cfmObj.isName("V2")) {
	    encVersion = 2;
	    encRevision = 3;
	    if (cryptFilterObj.dictLookup("Length", &cfLengthObj)->isInt()) {
	      //~ according to the spec, this should be cfLengthObj / 8
	      fileKeyLength = cfLengthObj.getInt();
	    }
	    cfLengthObj.free();
	  } else if (cfmObj.isName("AESV2")) {
	    encVersion = 2;
	    encRevision = 3;
	    encAlgorithm = cryptAES;
	    if (cryptFilterObj.dictLookup("Length", &cfLengthObj)->isInt()) {
	      //~ according to the spec, this should be cfLengthObj / 8
	      fileKeyLength = cfLengthObj.getInt();
	    }
	    cfLengthObj.free();
	  }
	  cfmObj.free();
	}
	cryptFilterObj.free();
      }
      stringFilterObj.free();
      streamFilterObj.free();
      cryptFiltersObj.free();
      if (encryptDictA->dictLookup("EncryptMetadata",
				   &encryptMetadataObj)->isBool()) {
	encryptMetadata = encryptMetadataObj.getBool();
      }
      encryptMetadataObj.free();
    }
    permFlags = permObj.getInt();
    ownerKey = ownerKeyObj.getString()->copy();
    userKey = userKeyObj.getString()->copy();
    if (encVersion >= 1 && encVersion <= 2 &&
	encRevision >= 2 && encRevision <= 3) {
      if (fileIDObj.isArray()) {
	if (fileIDObj.arrayGet(0, &fileIDObj1)->isString()) {
	  fileID = fileIDObj1.getString()->copy();
	} else {
	  fileID = new GString();
	}
	fileIDObj1.free();
      } else {
	fileID = new GString();
      }
      ok = gTrue;
    } else {
      error(-1, "Unsupported version/revision (%d/%d) of Standard security handler",
	    encVersion, encRevision);
    }
  } else {
    error(-1, "Weird encryption info");
  }
  if (fileKeyLength > 16) {
    fileKeyLength = 16;
  }
  fileIDObj.free();
  permObj.free();
  userKeyObj.free();
  ownerKeyObj.free();
  lengthObj.free();
  revisionObj.free();
  versionObj.free();
}

StandardSecurityHandler::~StandardSecurityHandler() {
  if (fileID) {
    delete fileID;
  }
  if (ownerKey) {
    delete ownerKey;
  }
  if (userKey) {
    delete userKey;
  }
}

void *StandardSecurityHandler::makeAuthData(GString *ownerPassword,
					    GString *userPassword) {
  return new StandardAuthData(ownerPassword ? ownerPassword->copy()
			                    : (GString *)NULL,
			      userPassword ? userPassword->copy()
			                   : (GString *)NULL);
}

void *StandardSecurityHandler::getAuthData() {
#if HAVE_XPDFCORE
  XPDFCore *core;
  GString *password;

  if (!(core = (XPDFCore *)doc->getGUIData()) ||
      !(password = core->getPassword())) {
    return NULL;
  }
  return new StandardAuthData(password, password->copy());
#elif HAVE_WINPDFCORE
  WinPDFCore *core;
  GString *password;

  if (!(core = (WinPDFCore *)doc->getGUIData()) ||
      !(password = core->getPassword())) {
    return NULL;
  }
  return new StandardAuthData(password, password->copy());
#else
  return NULL;
#endif
}

void StandardSecurityHandler::freeAuthData(void *authData) {
  delete (StandardAuthData *)authData;
}

GBool StandardSecurityHandler::authorize(void *authData) {
  GString *ownerPassword, *userPassword;

  if (!ok) {
    return gFalse;
  }
  if (authData) {
    ownerPassword = ((StandardAuthData *)authData)->ownerPassword;
    userPassword = ((StandardAuthData *)authData)->userPassword;
  } else {
    ownerPassword = NULL;
    userPassword = NULL;
  }
  if (!Decrypt::makeFileKey(encVersion, encRevision, fileKeyLength,
			    ownerKey, userKey, permFlags, fileID,
			    ownerPassword, userPassword, fileKey,
			    encryptMetadata, &ownerPasswordOk)) {
    return gFalse;
  }
  return gTrue;
}

#ifdef ENABLE_PLUGINS

//------------------------------------------------------------------------
// ExternalSecurityHandler
//------------------------------------------------------------------------

ExternalSecurityHandler::ExternalSecurityHandler(PDFDoc *docA,
						 Object *encryptDictA,
						 XpdfSecurityHandler *xshA):
  SecurityHandler(docA)
{
  encryptDictA->copy(&encryptDict);
  xsh = xshA;
  encAlgorithm = cryptRC4; //~ this should be obtained via getKey
  ok = gFalse;

  if (!(*xsh->newDoc)(xsh->handlerData, (XpdfDoc)docA,
		      (XpdfObject)encryptDictA, &docData)) {
    return;
  }

  ok = gTrue;
}

ExternalSecurityHandler::~ExternalSecurityHandler() {
  (*xsh->freeDoc)(xsh->handlerData, docData);
  encryptDict.free();
}

void *ExternalSecurityHandler::makeAuthData(GString *ownerPassword,
					    GString *userPassword) {
  char *opw, *upw;
  void *authData;

  opw = ownerPassword ? ownerPassword->getCString() : (char *)NULL;
  upw = userPassword ? userPassword->getCString() : (char *)NULL;
  if (!(*xsh->makeAuthData)(xsh->handlerData, docData, opw, upw, &authData)) {
    return NULL;
  }
  return authData;
}

void *ExternalSecurityHandler::getAuthData() {
  void *authData;

  if (!(*xsh->getAuthData)(xsh->handlerData, docData, &authData)) {
    return NULL;
  }
  return authData;
}

void ExternalSecurityHandler::freeAuthData(void *authData) {
  (*xsh->freeAuthData)(xsh->handlerData, docData, authData);
}

GBool ExternalSecurityHandler::authorize(void *authData) {
  char *key;
  int length;

  if (!ok) {
    return gFalse;
  }
  permFlags = (*xsh->authorize)(xsh->handlerData, docData, authData);
  if (!(permFlags & xpdfPermissionOpen)) {
    return gFalse;
  }
  if (!(*xsh->getKey)(xsh->handlerData, docData, &key, &length, &encVersion)) {
    return gFalse;
  }
  if ((fileKeyLength = length) > 16) {
    fileKeyLength = 16;
  }
  memcpy(fileKey, key, fileKeyLength);
  (*xsh->freeKey)(xsh->handlerData, docData, key, length);
  return gTrue;
}

#endif // ENABLE_PLUGINS